title: Phospho-regulation of kinesin-5 during anaphase spindle elongation.
abstract: The kinesin-5 Saccharomyces cerevisiae homologue Cin8 is shown here to be differentially phosphorylated during late anaphase at Cdk1-specific sites located in its motor domain. Wild-type Cin8 binds to the early-anaphase spindles and detaches from the spindles at late anaphase, whereas the phosphorylation-deficient Cin8-3A mutant protein remains attached to a larger region of the spindle and spindle poles for prolonged periods. This localization of Cin8-3A causes faster spindle elongation and longer anaphase spindles, which have aberrant morphology. By contrast, the phospho-mimic Cin8-3D mutant exhibits reduced binding to the spindles. In the absence of the kinesin-5 homologue Kip1, cells expressing Cin8-3D exhibit spindle assembly defects and are not viable at 37°C as a result of spindle collapse. We propose that dephosphorylation of Cin8 promotes its binding to the spindle microtubules before the onset of anaphase. In mid to late anaphase, phosphorylation of Cin8 causes its detachment from the spindles, which reduces the spindle elongation rate and aids in maintaining spindle morphology.
authors.affiliation: Department of Clinical Biochemistry, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva, 84105, Israel.
authors.forename: Rachel
authors.initials: R
authors.lastname: Avunie-Masala
authors.forename: Natalia
authors.initials: N
authors.lastname: Movshovich
authors.forename: Yael
authors.initials: Y
authors.lastname: Nissenkorn
authors.forename: Adina
authors.initials: A
authors.lastname: Gerson-Gurwitz
authors.forename: Vladimir
authors.initials: V
authors.lastname: Fridman
authors.forename: Mardo
authors.initials: M
authors.lastname: Kõivomägi
authors.forename: Mart
authors.initials: M
authors.lastname: Loog
authors.forename: M Andrew
authors.initials: MA
authors.lastname: Hoyt
authors.forename: Arieh
authors.initials: A
authors.lastname: Zaritsky
authors.forename: Larisa
authors.initials: L
authors.lastname: Gheber
mesh_terms: D000705:Anaphase; D016203:CDC2 Protein Kinase / Q000235:genetics / Q000378:metabolism; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism*
chemical_list: C075342:CIN8 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D016203:CDC2 Protein Kinase; D016547:Kinesins